1. Field of the Invention
The present invention relates to a friction agitation joining method and a friction agitation joining device for butt joining or stack joining metallic joining members such as aluminum members, and more particularly to, a friction agitation joining method and a friction agitation joining device for butt joining or stack joining a plurality of metallic joining members to preferably form a large joined member such as a floor member, a wall member, a ceiling member, a scaffold member, or the like.
2. Description of the Related Art
Conventionally, as a friction agitation joining method, which is one type or solid-phase joining method, the following method has been proposed. In the method, a joining device 110 as shown in FIG. 5 has been used. The joining device 110 is provided with a column-shaped rotor 111 having a larger diameter and a pin-shaped probe 112 having a smaller diameter. The probe 112 is integrally provided on an end of the rotor 111 so as to protrude along an axis Q of the rotor 111, and is made of materials harder than that of members 101, 102 to be joined (hereinafter referred to as "joining members"). While rotating the rotor 111 at high speed, the probe 112 is inserted into a butted portion 103, or there-around, of the two metallic joining members 101, 102.
Generally, such insertion of the probe 112 will be performed until a tip end of the probe 112 reaches a portion nearby a rear surface of the joining members 101, 102. In FIG. 5, a flat shoulder portion 111a, an end face, of the rotor 111 touches the joining members 101, 102. And then, while the probe 112 is inserted in the butted portion 103 of the joining members 101, 102, the probe 112 is advanced against the joining members 101, 102 along the butted portion 103.
At a portion of the joining members 101, 102 that the probe 112 contacts and there-around, the materials of the joining members 101, 102 will be softened by the friction heat generated due to the rotation of the probe 112 as well as the contact of the shoulder portion 111a of the rotor 111 and the joining members 101, 102, and agitated by the probe 112. In accordance with the advancing movement of the probe 112, the softened and agitated materials or the joining members 101, 102 are plastically fluidized to go around the probe 112 and to fill up a grove formed behind the probe 112 as it moves by the pressure caused by the advancing movement of the probe 112. Then, the materials will be cooled and solidified by the immediate loss of such friction heat. This phenomenon will be repeated with the advancing movement of the probe 112, which causes the joining members 101, 102 to be joined. In FIG. 5, the reference numeral 104 denotes a joined portion of the joining members 101, 102.
This friction agitation joining method has advantages in that the metallic joining members 101, 102 are not limited to specific kinds of materials because the joining method is one type of solid-phase joining method and the deformation of the joining members caused by heat stress is smaller as compared to melt joining methods such as a MIG welding method, a TIG welding method, or the like.
In the above-mentioned conventional friction agitation joining method, the joining members 101, 102 are fixed on a bed (not shown). The probe 112 is inserted into the butted portion 103 or the stacked portion of the joining members 101, 102. And then, the probe 112 or the bed to which the joining members 101, 102 are fixed is moved in a predetermined direction to join the joining members 101, 102.
To obtain a joined material with an uniformly joined portion, it is required to advance the probe 112 or the bed while the distance between the tip end of the probe 112 and the rear surface of the joining members 101, 102 is kept constant.
However, it is difficult to keep the distance constant along the whole length of the butted portion 103 or the stacked portion. Therefore, during the advancement of the probe 112 or the bed, the tip end of the probe 112 may stick out from the rear surface of the joining members 101, 102, or may not be inserted enough into the joining members 101, 102. Thus, it is difficult to obtain a joined material with a uniformly joined portion by the friction agitation joining method.